When Manhattan federal judge Denise Cote last month gave final approval to the $6.1 billion class-action settlement with WorldCom investors, it seemingly closed the books on the largest fraud in US history. Not so fast.

When Manhattan federal judge Denise Cote last month gave final approval to the $6.1 billion class-action settlement with WorldCom investors, it seemingly closed the books on the largest fraud in US history. Not so fast.